Uniting the component parts of composite sheet-metal structures.



A. F. RIETZEL.

UNITING THE COMPONENT PARTS OF COMPOSITE SHEET METAL STRUCTURES.

APPLIOATION FILED PER 24, 1905.

a Q i] WIT/V5885? lNl/E/VTUR E 41.494 Field 7 B) whoku. Wfi ATTORNEYS UNITED sTATEs AD'OLPH r. RIETZIEL, or LYNN,

MASSACHUSETTS, ASSIGNOR TO THOMSON r rrsnr OFFICE,

ELECTRIC WELDING'COMPANY, OF LYNN, MASSACHUSETTS, A CORPORATION OF MAINE.

Specification of Letters Patent.

Patented July 20, 1909.

Application filed February 24, 1905. Serial No. 247,081.

To all whom it may concern:

of Lynn,

of Massachusetts, (with post-oflice address Be it known that I, ADOLPH F. RIETZEL, a citizen of the United States, and a resident in the county of Essex and State Lynn, Massachusetts,) have invented certain new and useful Improvements in Uniting the Component Parts of Composite Sheet- Metal Structures, of which the following is a specification.

My invention relates-to the manner of uniting or fastening two pieces of metal to one another and its object is more particularly to afford a substitute for the manner of unitin pieces of metal as heretofore practiced in t e art of electric Welding.

As applied tosheet metal manufactures the object is to afford a cheap and practical substitute for riveting and other methods of mechanicall securing the two pieces of metal toget er. .As applied to this branch of the metal working arts, the invention affords a means whereby articles of composite sheet' metal manufacture may be madeup by fastening the pieces ofmetal constituting the structure with'a perfectly secure union and by a process that can be economically conducted.

'Briefiy stated, the invention consists in electrically welding pieces together in spots definltely located in and involving'a portion only of their meeting surfaces, by the application of pressure and heating current localized in such spot or spots.

By the terms weld and as herein employed I refer electric weld to that process of welding in which the metal is brought to plastic condition by passing an electric current from one to the other of two pieces where they are in contact and is welded while in such condition by the application of pres-' sure, as contra-distinguished from a process effected lb melt' which, is iflerent om welding dina'ry sense of 'e manufactures, in that the metal is heated 'beyond the point ofplasticity and pressure is not em loyed. v

'- :It has. hbefore proposed to electr cally of uniting metals, which is described in a No. 363,320,. dated; in which the union is, the metal by an arc and, in the "or' d to metal platent to Bernardos, ay 1-7, 1887, and

the term as app weld two rods of metal together by a buttwelding process, the area of union effected being substantially coextensive with the cross-section ofthe pieces at their meeting ends, that is to say, the weld has been made over substantially the whole area of the opposed portions of said pieces. It has also been proposed to make a lap joint. between the ends of two strips of metal by electrically unitin them together over substantially the w ole area of the lapping surfaces. A weld formed according to my invention is distinguished however from such prior welds by the fact that the opposed surfaces are welded together in spots only, the heating electric current being localized or confined in any desired way to such spots so that the major portion of the opposed surfaces will not be involved in the Welding, although they may, after the com letion of the operation, lie in contact wit one another or very close together.

' My invention is particularly valuable in fastening of pieces of sheet metal together because not'only does it limit the amount of electric energy required very considerably as com ared with the prior methods of union, but it also diminishes the liability to burn? ing of the metal which'isliable to occur when the attempt is madeto form a union of two sheets of metal by an electric welding process over substantially the whole areaof the meeting or opposed surfaces.

In carrying out my invention any desired such number depending obviousl u on the extent of the meeting surfaces wiiicii are to be fastened together and also upon the strength of the union desired.

In carrying out -m invention the localize ;t ion of the flow, of eating electric current and of weldi pressure to the desired spot or s ots may e brought about in any desire way. One of the preferred ways is by roviding betv's' een the meeting surfaces or portion's of the pieces to be united suitable condncting rojections or points at the spots ofn'rijii'on, w 'ich projections or points carry- :ing the heating'elect'i'ic current from one gpie'c to the othe'r'are so located-in the meeting surfac'e's-v and number of spots of union may be employed,

are so separated from one another that on the application of the weld ing pressure the welded union resultin will be localized in the areaof the oppose surfaces and will be substantially coer'rtensive in area with'the restricted area of-the path of the effective heating current. Various ways of providing such points or projections I will occur to those'skilled in the art.

The preferred method is to indent the metal from the side reverseto that on which the union is effected by a suitable tool, the projections thus formed affording points for the passage of the electric current. This method is preferable also because it permits the welding to be. produced at a multiplicity of spots simultaneously tlfrough the application of pressure overthe whole rear surface of the plate, the points or projections in that case serving not only to localize the flow of the heating current but also to localize the welding pressure.

In the preferred manner of carrying out my invention in the case of sheet metal manufacture I provide projections from the meeting surfaces of both pieces that'are to be united. Said projections may also be provided by interposing between the two plane sheets small pieces of conducting material which actin the same manner when the sheets are brought together, as projections which localize the heating current and the pressure. It will be understood, however, A that in the latter instance as in the former, these pieces are so small and are placed such a distance apart that on the application of welding pressure there will be no running of? the welds into one another but that the final union will be in spots only leaving well-defined areas on the meeting surfaces, in which the surfaces either lie in contact or separated from one another by a very thin space: From the foregoing it will be seen that my invention is distinguished from prior methods of welding pieces of'me'tal together in that it may be very cheaply practiced, be- 45 cause'noattempt is made ,to weld .over the whole of the opposed surfaces of the welded pieces; but on the contrary the union is at a spot or'spots onlywhich in ordinary cases will afford as strong a union as would be pro duced by the riveting of the piecesr. v .The invention further has the advantage "that not nearly so much electric energy is requlred as is ngfleessary when the electrically welded union extends over the whole area of the opposed surfaces. Moreover, the danger .of burning when the attempt is made to-weld two sheets of metaltogetherby a lap weld is largely eliminated. v v

.ln,the accompanying drawings Figures 1, 2,3, {I and 5;i'llustrate some of the ways in which the pieces of metal to be'united may be preparedv for the welding according to my invention. Figs. 6, 7 ,8, and 9 show modifications in the form and disposition of the 65 contact projections which result in the spots the sheets and Figi on both pieces. ,1

elongatedand irregularly or symmetrically teaser of electrically welded union. Fig. 10 shows the assembling of three plates together for weldingaccording to my invention.

In the various figures of the drawing the invention is illustrated as carried out with 1 two sheets of metal BLB. In Fig. 1, plate B. only is provided with the distinct or isolated spots (0) or projections for the flow of the electric current, to the plate B. which spots or points may be formed by indenting 7 the plate with a suitable tool. The spots are located so far from one another that on the application of ressure coincidently with the flow of electric current from one plate to the other there will be a number of distinct 8 areas or spots ofelectrically welded union of the plates separated by well-defined areas on the meeting surfaces in which no union takes place. The resultant is however a fastening of the plates together securely and which is 8 practically as effective as if the attempt were made tojform a welded union over the entire areas of the meeting surfaces. Obviously, e the greater the distance between the spots the lesser the number that would be used and 9 hence the lesser the consumption of energy in efiecting the weld. This is of considerable importance Where the meeting areas are large or where a considerable amount' of work has'to be done. The welding pressure 9 is conveniently applied by conducting-blocks or electrodes, A, A, between which the two pieces B, B, are assembled. These electrodes, A, A, furnish the heating current while applying the pressure, the localization 1 of the pressure in the spots being brought about in this instance by the poihting of the surfaces at ,point c. In Fig. 2 *both'plates are rovided with projections the points of WhiC II engage with ll one another, the pointing being produced by indenting the metal sheets from the rear.

Fig. 3 illustrates the localization uf the welding by casting projections upon one of 4 by casting projections 1 e localization of the weld ing in spots might be effected as illustrated in Fig. 5 by interposing small pieces of metal at the spot or spots of desired union, these pieces operating when the plates are brought together in the same way as the projections before referred to. The number and size of the pieces and theirdistance apart is in this case, as before,.so chosen'that the application'of pressure together with the'flow of heating current from one plate to the other willresult in a union ofthe two pieces over their opposed surfaces in spots only thereon.

' Fi 6 shows how} thespots might be dispose "to fasten the pieces together in distinct 12 spots around theiredges.

As shown in Figs. 7xand 8 the projections, instead of'being rounds might besomewhat arranged.

new

Fi 9 shows round and somewhat -elongate rojections combined.

1 those instances'however, the union 1 sure may be greatly varied without departin from my invention.

ig. 10 illustrates the welding of three plates of sheets together when superposed.

My invention 1s es ecially useful'm the manufacture of artic es from sheet metal which are stam ed out to different forms, and which have heretofore had their com onent portions united by riveting or ot er 'by melting purely mechanical expedient which is not on expensive but requires -generally special tools and results in many cases in an insecure union. When the invention is employed in its preferred form or manner of practice in the field 'of sheet metal manufacture all that is is to provide the contact s ts or projections as'already described'and. t en to assemble the pieces in an electric welding machine and weld them' together as already set forth. I

The roduct of the foregoing process is readilydistinguishable from that roduced down the metal of t e ieces from the back at spots as proposed int ebefore mentioned atent of Bernardos in that there is no su stantial alteration of condition of the metal back of the welds appearing as aburning, roughening or disintegration of the material by the very great heat of the electric are employed for meltin down the metal, and by the further fact that the unions theniselves in the material of the juxtaposed or opposite faces have the characteristlcs of a true weld produced by bringin the metal to welding temperature only an applying pressure, so that the pieces are solid y and firmly united and cannot be readily tornapart as they could be if the metal at the spots has been melted down under the high tem erature of the electric arc. 1 a

T e product in the'form of sheet metal is further particularly useful for sheet metal ware since the outer or exposed surface of the metal will have the smooth and practically unaltered finish of sheet-metal and said surface will not be substantially marred, when the rocess is properly conducted, exce ting for t e presence of such -infrequentsma lderessions as mi hti'remain from the previous indentation of t e, metal from the back when, as hereinbefore described, an indenting of the metal may be resorted to. The product in sheet metal also possesses the advantagethat the spots of welding when located within the edges of the meeting metal.

superior to that produced by riveting of theplates in that there are no rivet heads to mar the finish of' the back or outer surfaces of the What I claim as my invention is: v 1. The 'hereinbefore described improved method of fastenin two iece's of metal together by electrica 1y we dingthemto one another at spots only of their juxtaposed;

surfaceswilll not show. The-product is also' v opposite faces by the application of and heating current localizedin suc spots.

The herein described method of'umting two pieces ofmetal at a numberof distinct or separate spots separated from one another by, well-defined areas of no union, consist ing in applying pressure localized at the spots of desired union, and passing-electric current through the pieces from one to the other while confining the flow of current to said s ots until the union is effected.

llhe herein described method of'uniting two pieces of metal, consistin in pressing them together while passing a eating electric current from one to the other and localizing the flow of current and the heating throughout the operation in a spot or spots of circumscribedor limited area as compared with the area of the immediately 0 posed surfaces so as to limit the union of t 1e pieces to a spot or s ots. I 4. The improve method of uniting two pieces of metal at a spot or spots only in their opposed meeting surfaces, consisting in pressing the two pieces together, and pass ing a weldin electric current from one to the other whi e localizing the pressure in and confining the flow of current to the spot or spots of desired union so asto produce an isolated spot or spots of union, leaving dis- I by pressing them together and at the same time passing a heating and welding current from one to the other at a spot on their meeting surfaces which is restricted in area throughout the o oration so as to leave on the meeting sur aces a well-defined and comparatively extensive area of no union completely surrounding said spot.

7. The method of weldihg two pieces of metal together, consisting in superposing' said pieces with their, surfaces at which the union is to take phage superposed or presented to one another, pressing the pieces together, and passing a heating electric cur rent from one to the other while localizing the heating current simultaneously in a number of distinct or separate spots of limited area, separated from one another sufliciently to secure a union of the pieces in a number of corresponding distinct spots surrounded by and separated from one another by dis tinct areas in which no union exists.

8. The method of uniting two pieces of metal, consisting in providing between their meeting surfaces a number of projections, spaced apart as described, pressing the pieces together; and passing an electric current through said projections while confining the Welding area of such current to said projections so as to leave distinct areas around spots in which no welding shall be produced.

9. The method of fastening two plates of metal together at a multiplicity of distinct or separate points of welded union, consisting in roviding between them a number of isolate contact spots adapted to pass an electric current from one to the other but so separated that the electric welds will be separated from one another by unwelded areas, passing a heating electric current through such spots simultaneously and applying pressure as and for the purpose described.

10. The herein described method of electrically welding two plates or sheets of metal of any gage together by distinct spots of union disposed over their plane surfaces, consisting in providing a multiplicity of electrical contact. spots coincident with the separated spots of union and dis osed at such distances'apart that there wil be welldefined areas between s ots through which the electric current wil not flow, passing electric current from one plate to the other through said contact spots'simultaneously and a plying pressure as and for the purpose described.- I I 11. The method of fastening two sheets of metal together, consisting in providing between thema number of isolated contact spots for the passage of the electric welding current, said spots being adapted to initially hold theplates apart and being separated from one another a sufficient distance to confine the welding to distinct areas or iso lated spots, passing a heating electric cur: rentthrough a number of said contact spots simultaneously and pressing the gether as and for the urpose descri ed.

I 12. The method of fastening two plates of metal to ether, consisting in furnishing a surface 0% said plates witha number of prov jecting contact spots for the passage of weldmg electric current and disposed at such distances apart that on theapplication of pressure the welds will not runinto one another,

theless, firmly hold the lates to- Marci superposing said plates, passing a'heating' clectrlc current from one to the other over said separated spots and a plying the ressure to produce a spot-wel ing of the p ates to one another as and for the purpose described.

13. The herein described method of fastening two pieces of metal to ether by providing each plate with a num er of pro ecting contact spots on its plane surface disposed at such distances apart that the unions will not run into one another but will, neverlates' together, superposing said plates Wit the'pro ecting spots in simultaneous engagement with one another, passing a heating electric current from one late to the otherthrough the spots and simu taneously applying pressure thus uniting the plates at a number of distinct points of welded union.

14. The method of uniting two sheets of metal face to face, consisting in indentingthe material, superposing the plates with the points of the indentations engaged, passing an electric current from one plate to the other through said points simultaneously, and applying pressure while confining the area of eating to welding temperature to a circumscribed area or spot entirely surrounded'by areas unheated to welding temperature to unite the pieces in a distinct spot or spots of small extent in the Whole area of the op osed faces.

15. he herein described method of fastening two plates to ether at a multiplicity of distinct mechanica ly separated points of welded union, consisting in indenting each plate to form a number of projecting contact spots on the plane surfaces which are to abut, superposing said plates with the projecting spots in simultaneous engagement with one another, passing a heating electric current from one plate to the other-thereby forming a number of distinct 'zonesor points of heated metal, heated to Welding temperature, and applying pressure to complete the union of plates by a number of mechanically distinct unions."

16. Metal plates fastened together by a number of distinct or isolated Welds on their meeting surfaces and in spots comprising meeting portions of the metal plates, the

backs of said plates being practically unaltered in their metallic condition and the spots on the meeting surfaces being separated from one another by distinct unwelded areas. 17. Sheet metal work comprising pieces of sheet metal welded together in the material of their meeting surfaces and in spots only, each surrounded by distinct areas of unwelded union, the back surfaces of said pieces being substantially unaltered over the welded s ots, substan i-ally as and for the purpose escribed.

18. Composite metal work having its comnent pieces welded together in spots only involving the material of their opposed or meeting surfaces, said spots being each entirel surrounded by distinct areas of unwel ed union and the portion of the pieces- -back of the welds being substantially unaltered, as and for the purpose described.

over said spot, as and for the purpose de scribed.

20. A metal article comprising two bodies.

of metal having adjacent plane surfaces united at a plurality of spaced and isolated spots of integral and autogenous welded union, the metal at the spots of Welded union having substantially the same qualities as at other points.

Signed at Lynn in the county of Essex and State of Mass this 7th day of Feb. A. D. 1905. I

ADOLPH F. RIETZEL.

Witnesses:

EDWIN W. HAWEs, E. I. Fos'rER. 

